ABB Ltd

About: ABB Ltd is a company organization based out in Zurich, Switzerland. It is known for research contribution in the topics: Voltage & Signal. The organization has 6222 authors who have published 6852 publications receiving 83994 citations.

Three-point converter and method for its operation

Abstract: A three-point converter with NPC diodes disposed between bridge halves and a center tap of an intermediate circuit is proposed. A decoupling network is provided for the upper bridge half, a first input of which decoupling network is connected to a positive pole of the intermediate circuit and a first output of the decoupling network is connected to a positive pole of the three-point converter. Furthermore, provision is made of a further decoupling network for the lower bridge half, a first input of the further decoupling network is connected to a negative pole of the intermediate circuit and a first output of the further decoupling network is connected to a negative pole of the three-point converter. The remaining inputs of both of the decoupling networks are connected to the center tap of the intermediate circuit. The remaining outputs of both of the decoupling networks are connected via the NPC diodes to the upper and lower bridge halves. A commutation voltage for the main switches of the upper and lower bridge halves is decoupled from a halved intermediate circuit voltage (V dc /2) independently of one another by the decoupling networks.

Determining parameters of an equivalent circuit representing a transmission section of an electrical network

Abstract: A method for determining an equivalent impedance of a transmission section of an electrical network, includes representing the transmission section as having at least two interfaces with other sections of the network. For each interface, a voltage phasor and a current phasor flowing through the interface are determined from simultaneously made measurements at the interfaces. From the phasors, the equivalent impedance is calculated. The required simultaneousness of the phasor measurements is achieved by means of Phasor Measurement Units (PMUs) that are synchronized via the Global Positioning System (GPS).

Method of brazing directionally solidified or monocrystalline components

Abstract: In a method of brazing directionally solidified or monocrystalline components, the brazing deposit and the directionally solidified or monocrystalline component are moved through a heated zone. In this zone, the temperature applied by a heating system is greater than the liquidus temperature of the brazing alloy and less than the local incipient melting temperature of the component. A thermal gradient is applied between the component and the brazing deposit.

Arrangement for influencing the radial clearance of the blading in axial-flow compressors including hollow spaces filled with insulating material

Abstract: In an arrangement for influencing the radial clearance of the blading of an axial-flow, highly loaded compressor which essentially comprises a rotor (1) equipped with moving blades (2) and a blade carrier (3) which is equipped with guide blades (4) and is hung in a casing (5), the blade carrier (3) has long and narrow mountings (7) for the guide blades (4), at least one hollow space (9) being arranged in the guide-blade roots (8), a hollow space (10) being present in each case in the embedded state in the peripheral direction between the guide-blade root (8), the two mountings (7) for a guide blade (4) and the blade carrier (3), a further hollow space (11) being present in each case in the peripheral direction between the blade carrier (3) and the mountings (7) for two successive guide blades (4), which hollow space (11) is defined by a plurality of segments (12) distributed over the periphery and connected to the guide-blade roots (8), and the hollow spaces (9, 10, 11) being filled with insulating material (15).

EHV AC and HVDC transmission working together to integrate renewable power

Abstract: Renewable resources in North America are extensive and are expected to represent a growing share of total resources. Large hydro and geothermal resources are concentrated in fixed locations and can be readily dispatched. Wind and solar resources are more dispersed, remote from major load centers, and variable in their output. New electric transmission infrastructure is needed to access newly developed renewable resources. For optimal transmission development, it is essential to take a long term approach that reflects the characteristics of the sources being connected. The transmission system must have capacity to aggregate these diverse renewable sources, transport usable blocks of power to remote load centers and disperse the power to load serving entities in an efficient and reliable manner.